<template>
  <div class="spec-preview">
    <img :src="mySkuInfo.skuDefaultImg" />
    <div class="event" @mousemove="maskFlow"></div>
    <div class="big">
      <img :style="{ left: -left * 2 + 'px', top: -top * 2 + 'px' }" :src="mySkuInfo.skuDefaultImg" />
    </div>
    <div class="mask" :style="{ left: left + 'px', top: top + 'px' }"></div>
  </div>
</template>

<script>
import { mapGetters } from 'vuex'
export default {
  name: "Zoom",
  data() {
    return {
      // left和top代表遮罩的定位值
      left: 0,
      top: 0,
      // vuex中的detail模块拿到skuInfo数据
      mySkuInfo: {}
    }
  },
  // 从vuex中的detail模块拿到skuInfo数据
  computed: {
    ...mapGetters('detail', ['skuInfo'])
  },
  // 监听skuInfo数据
  watch: {
    skuInfo() {
      this.$nextTick(() => {
        this.mySkuInfo = this.skuInfo;
      })
    }
  },

  methods: {
    maskFlow(e) {
      // e.offsetX, e.offsetY
      // 一、遮罩随鼠标移动
      // 鼠标居中遮罩层，并使其随鼠标移动
      this.left = e.offsetX - 100
      this.top = e.offsetY - 100
      // 判断遮罩位置，限制其运动范围
      // 左右
      if (this.left <= 0) this.left = 0;
      if (this.left >= 200) this.left = 200;
      // 上下
      if (this.top <= 0) this.top = 0;
      if (this.top >= 200) this.top = 200;

      // 放大图随遮罩移动

    }
  },
}
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover~.mask,
  .event:hover~.big {
    display: block;
  }
}
</style>